[vsnet-grb-info 13828] GRB 130831A: Weihai optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15142
SUBJECT: GRB 130831A: Weihai optical observations
DATE:    13/08/31 14:29:36 GMT
FROM:    Dong Xu at DARK/NBI  <dong.dark at gmail.com>

D. Xu (DARK/NBI), C. M. Zhang, C. Cao, S. M. Hu (SDU) report:

We observed the field of GRB 130831A (Hagen et al., GCN 15139) using
the 1m telescope located in Weihai, Shandong Province, China, and
2x600s SDSS r'-band frames were obtained.

The optical afterglow is well detected at the UVOT position in each of
the two images with rather fast decaying rate. Following photometry is
calibrated with nearby SDSS stars:

Mag     MagErr   MeanTime(T-Ttrigger, hr)
14.35    0.04           0.3356
15.66    0.05           0.6575